A Shell of Himself
by CJtheStoryteller
Summary: Set after 'Mutagen Man Unleashed.' Determined to keep his promises to change Timothy and April's father human again, Donatello pushes himself beyond the point of exhaustion while working nonstop to create a retromutagen. It's up to Donnie's big brother, Leonardo, to stop the genius turtle from sacrificing himself and help him see his own self-worth.
1. Chapter 1 - Caught Green-handed

**_*Disclaimer: I do not own the rights to the Teenage Mutant Ninja Turtles franchise._**

 ** _Author's Note: Here's chapter 1 of 'A Shell of Himself.' I hope you like it. Thank you to everyone who has taken the time to provide feedback and favorited/followed me. I really appreciate the support._**

* * *

 **Chapter 1 – Caught Green-handed**

The system tray clock on the bottom right hand corner of his computer monitor informed him that the exact time was 3:06 A.M. The font of the digital clock was almost too tiny for his tired eyes to read, but all he had to do was slant his body forward slightly and squint a few times to bring the numbers into focus. Well, focused enough so that he could decipher them.

Donatello dragged his olive-green colored hands down his face and then rested his carapace against the worn back of the task chair he was stationed at.

 _3:06 A.M._

That meant that he was supposed to have gone to bed four hours and four minutes ago. The reason he knew precisely how long it had been since he was supposed to have gone to bed was because it had been 11:02 P.M. on that same desktop clock when his oldest brother, Leonardo, had ever-so calmly placed his hands down on the top of Donatello's desk, leaned over him, and ordered him to turn off all of his equipment in the lab and call it a night.

Now that it was past the three o'clock hour – ante meridiem rather than post meridiem – Donnie realized that he couldn't really call it a night any more. Not if he wanted to be entirely accurate, which he did. Technically, if he went to bed now, he would be calling it a morning. Of course, Donatello had no intention of calling it a morning at this point, even though he was well aware that Leonardo would be seriously ticked off if he found out that his little brother had directly disobeyed him and forgone sleep again, just as Donnie had done the past five nights.

Sure, Donatello felt a little guilty for defying his oldest brother's very explicit commands. _Okay, strike that_ . . . He felt a lot guilty for defying Leo's commands, but, in Donnie's defense, he had shut down _most_ of his equipment and switched off _almost_ all of the lights.

 _That had to count for something, right? Okay, maybe not . . ._

Truth be told, Donnie hadn't turned off any of those things out of the goodness of his heart or even just to appease his sometimes overbearing oldest brother. No, Donnie had done those things to protect his own shell. Not for selfish reasons. Being selfish wasn't in Donatello's nature. It was well-known that the dubbed genius of the Hamato Yoshi family did not have a selfish bone in his body. All of his close-knit friends and family would personally vouch for that. Donatello always put others' needs before his own, hence the reason he was currently depriving himself of all sleep and nutrition. He was doing so out of purely unselfish reasons. He was trying to help his friends. Friends that he had recently made solemn promises to that he fully planned to keep, and, in his mind and his heart, those vows came before fulfilling any basic needs that he might have. So for the past five nights, instead of wasting time on trivial things like eating or sleeping, Donnie had locked himself away in his lab, day and night, so that he could work on the cure that he had promised to find. He had promised his friend, April O'Neil, and he had promised his friend, Timothy (aka 'The Pulverizer'). Donnie had no intention of breaking his promises.

Now, more than ever, it was imperative that Donatello develop an antidote for mutagen as soon as possible, above _all_ else. His friends were counting on him. That was why Donatello was pushing himself so brutally hard to find a cure. He had been ever since the unfortunate incident with Timothy . . .

Six nights ago, Donatello had been forced to make a difficult choice. One that Donnie wasn't so sure he could live with himself for making, even though, deep down inside, he knew without a doubt that it was the only viable choice he had. In order to save his three brothers and the human girl he was head over shell in love with from a crazed mutagen monster, Donnie had no choice but to take that monster out. And take it out he had. To be exact, he had tricked the demented creature into ingesting an unsuccessful, highly experimental batch of retromutagen Donnie had made earlier in the day. The altered mutagen had effectively froze the creature solid inside of a glass containment unit, just as Donnie had anticipated.

The problem was, that crazed, now-frozen monster had been Donnie's friend. That mutated monster that had tried to hurt them was once a human boy. A rather inept, flabby, obtuse human boy that called himself 'The Pulverizer,' but a human boy nonetheless.

Looking back now, Donnie couldn't help but to blame himself for the human boy's most unfortunate fate.

On multiple occasions, Donnie and his brothers had saved 'The Pulverizer' (whom they later found out went by the common name of Timothy) from getting . . . well, pulverized. Timothy was a bit of a – for lack of a better word –nincompoop. The teenager wanted to be New York City's next big hero, but he lacked any kind of actual skills or abilities. Mostly, he was just a klutz. Donnie's brothers had thought of Timothy as nothing but a hopeless loser/bumbling idiot. Actually, everyone seemed to think Timothy was pretty much 'expendable.' The Kraang . . . The Foot clan . . . Heck, even Donatello's father (aka Hamato Yoshi, aka Master Splinter, aka Sensei) had referred to Timothy as a 'doofus,' and Master Splinter had always taught his sons about the values of humanity and compassion. Not once before did Donnie remember a time that their father, who just so happened to be a giant rat as well as a grand master of Ninjutsu, had called someone a hurtful name only a few seconds after meeting them. That was perhaps a true testament of just how extraordinarily incompetent Timothy was.

Still, Donnie had felt sorry for the boy. Maybe that was because Donnie felt as though he could somewhat relate to Timothy's situation. Granted, Donnie was never quite as pathetic as Timothy had been, but Donnie knew what it was like to be looked down upon. Donnie was also quite familiar with what it felt like to try your best and still not be good enough in the eyes of those you most admire. Donnie had always been the weakest fighter in a family of gifted ninjas. No amount of studying, training, or practice could ever make Donnie as good as his brothers were at martial arts. Donnie had long ago accepted the harsh reality that his three brothers were natural born ninjas and he . . . was not. He would never be as good as them. The acceptance of that reality didn't mean the truth hurt any less.

It had been Donnie's severe insecurities about himself, combined with his kind heart and gentle soul, that had ultimately caused the normally brilliant turtle to suffer a major lapse in sound judgment and decide to try to help Timothy. Donnie had even gone so far as to show Timothy some basic Ninjutsu moves so that the kid could at least have a chance at defending himself. It was a decision that Master Splinter hadn't exactly been too keen on.

Donnie could still hear his father's words replaying in the back of his head when he had told Master Splinter that he just wanted to teach Timothy some rudimentary skills.

" _If you train him, you are responsible for whatever happens . . ."_

Propping his elbows up on his desk, Donatello buried his face in his shaky hands. Tears started to sting his droopy eyes, but he blinked the moisture back as quickly as it had formed. He refused to allow himself to cry. This was not the time to fall apart like some useless weakling. Timothy deserved better than that . . .

 _Timothy . . ._

" _. . . you are responsible . . . you are responsible . . . "_ The words repeated in Donnie's head like a demotivational mantra.

So much time had passed since Timothy's horrible transformation, yet Donnie could still vividly recall the events that had lead up to Timothy being mutated into a barely sentient glob of intestinal goo as if it had happened only yesterday.

" _Shredder's gonna mutate just one Foot soldier first as a test. And guess what? I volunteered!"_

" _What?"_

" _I know! Isn't that cool?"_

" _No! Why would you think that's cool?"_

" _This is my chance to be like you guys. Throw some mutagen on me and boom! I'm a superhero. I'm taking Shredder down!"_

" _The mutagen is dangerous! You have no idea what that stuff could do to you!"_

Despite Donnie's repeated warnings about how unpredictable and unstable mutagen was, Timothy's delusional fixation on becoming a hero had made it impossible to get through to him. The boy's mind was set and he completely – and foolishly – disregarded Donnie's vain attempts to stop him.

" _Timothy, no! What are you doing?"_

" _I'm gonna be a mutant like you!"_

" _Um, doing the mutation thing is notoriously unpredictable . . . AND REALLY STUPID!"_

In the end, all of Donatello's desperate efforts to save the human boy from himself just weren't enough. Donnie wasn't able to stop Timothy from willingly dousing himself with mutagen, nor was Donnie able to prevent Timothy from mutating into what Donnie's second oldest brother, Raphael, later referred to as a pile of guts in a jar. A crass remark, but rather apropos.

What Donnie's most uncouth brother, Raph, had meant when he had said 'jar' was the mutagen containment unit that they had stored Timothy's mutated blob-like form in while Donnie tried to synthesize a retromutagen to cure Timothy's condition. Since his mutation, Timothy had been housed in that unit in Donnie's lab up until six days ago. That was when Timothy managed to get into one of the full mutagen canisters on Donnie's desk. Consuming the mutagen caused Timothy to sprout a pair arms and legs from his containment unit, which allowed Timothy the mobility and strength needed to break out of the lab and wreak havoc on the streets of the city.

Timothy's secondary mutation had made him extremely volatile and dangerous . . . _like even more so than Raph on a bad day_. 'The Pulverizer' spiraled out of control and tried to destroy the turtles. Much to his dismay, Donnie had no other option than to put his friend into an indeterminate cryogenic state, essentially turning poor Timothy into a giant popsicle in order to protect his brothers from being smashed and/or melted by Timothy's acid hands. In addition to protecting his brothers, Donnie also had to protect their friend, April, who had been the one Timothy was actually going after. All because Donnie had talked about April nonstop in front of Timothy. Donnie had put her life in danger with his whining.

 _Ah, April . . . sweet April . . ._

Yet another friend that Donnie had let down.

April hadn't talked to the turtles for weeks now. Not since her dad's mutation.

Yet another mutation that Donnie was responsible for . . .

Several weeks before, Donnie had discovered via a Kraang communication orb that the Kraang were back and were using one of their stealth ships to transport a shipment of unknown cargo. With the help of April and her father, Kirby, the turtles tracked down the stealth ship and boarded it only to discover that the Kraang were transporting mutagen canisters. Lots and lots of mutagen canisters. While the turtles were fighting the Kraang aboard the ship, several tactical errors that Donnie was not proud of were made, which resulted in dozens of mutagen canisters plummeting down upon the city, including the one that landed on April's father and turned him into a giant bat-like creature.

Donnie could still remember the horror that had befallen across April's face when his younger brother, Michelangelo, had revealed to her that they had been the ones responsible for dropping the mutagen containers on the city.

" _Listen. Don't blame yourself, April. It was our fault. We spilled the mutagen. We'll fix it."_

" _What? Y– you guys . . . You guys spilled the mutagen?"_

Upon seeing how upset April was, Donnie had tried to comfort her to no avail.

" _I swear by Darwin's beard we'll cure him."_

" _You mutated my father!"_

April had no sooner finished that sentence when her father escaped the large cage the turtles had trapped him in. Kirby bat or 'WingNut' (per Mikey) had tried to grab April, but Donnie had knocked him away with his bo-staff. Then, the bat/human mutant had flown off into the night, leaving a very angry and devastated April behind.

Again, Donnie had tried to console April, but the second time that he had reached out to her, she had jerked away as if she was repulsed by his very presence.

Then, she had spoken the words that Donnie would never forget, and though she had been speaking to all of them, she had looked at right at Donnie when she had said them.

" _Don't! Don't touch me! You keep away from me! I never want to see your faces ever again!"_

That was when Donatello's heart had been broken into a million infinitesimal pieces. The expression April had given him that night was nothing short of gut-wrenching. Her big, blue eyes had never looked at him that way before. It was as if she hated him.

Regrettably, April had stayed true to her word. She hadn't stopped by the Lair or even attempted to contact them since the incident. Donnie had tried several times to call the T-phone he had made for her, but she had turned it off, apparently doing everything she could to avoid them altogether. Donnie, on the other hand, could not avoid her. Not completely. Though it shamed him, he had followed her in secret multiple times to check up on her . . . just to make sure she was okay.

Okay, maybe that was a little bit creepy in a stalker sort of way, but Donnie was worried about her. She had been so upset and it was Donnie's fault. He hated himself for hurting her.

That was why it was so urgent for Donnie to find a formula that would make mutated cells turn back to normal. Maybe if he cured Mr. O'Neil, April would find it in her heart to forgive him. Then, maybe – just maybe – he and April could be friends again. Plus, if Donnie could find a way to reverse engineer mutagen into retromutagen, that might mean he could save Timothy, as well.

Of course, getting his friends back was all contingent on whether or not he could develop some sort of an antidote, and, thus far, that endeavor was not going so well.

Pulling his hands away from his face, Donnie looked to his left at his latest of many failed experiments on his desk and let out a lengthy sigh. He then looked back at the clock on his computer screen again.

 _3:14 A.M._

Morning practice started in a few hours. Time was ticking away and he was still no closer to a cure than the night before or the night before that . . . That meant that, most likely, tomorrow night would be another sleepless night.

 _Way to suck, Donnie. At least you're consistent . . ._

Pressing the tips of his thick fingers firmly into his aching eye sockets, Donnie tried to massage away the sleep, the killer migraine coming on, the burning sensation, and any wetness that may have accumulated without his knowing. His body was beginning to show indisputable signs of overfatigue that would have concerned him if it had been anyone other than him exhibiting the same symptoms, but Donnie couldn't afford to worry about such things right now, nor could he allow his body to just conk out on him like it was threatening to do. He owed it to April and Timothy to keep working and he wasn't going to let something like sleep deprivation or the onset of an epic headache stop him. They deserved better than that.

 _They deserve better than me . . ._

Drawing in a deep breath, Donatello tried to shake off his dreary thoughts. What he needed was an instant pick-me-up and he knew just the remedy. Donatello reached for his favorite coffee mug filled with an extra strong serving of now room temperature liquid caffeine and guzzled the remaining contents of the cup down, savoring the all-too-fleeting bitter taste that rolled down the back of his dry, scratchy throat.

 _That ought to do the trick. Just need to get the brain stimulated again is all . . ._

As he waited for the caffeine high to kick in and hopefully give him his fifteenth or sixteenth wind (he had lost count of which wind he was on hours ago), Donnie used the heel of his foot to turn his blue office chair about ninety degrees so that he could lay eyes on Timothy's containment unit, thinking maybe it would summon some much-needed inspiration. He immediately regretted doing so. Not just because of the guilt that devoured away at him when he stared at Timothy's frozen form, but also because he was so dizzy, he just about fell out of his chair.

Turning back towards his desk so he could use it for support, Donnie pushed his empty ceramic mug aside to make room for the scientific equipment necessary to conduct his next experiment.

The morning was still young and there was much work to be done.

* * *

The clock beside him read 4:15 A.M.

If he fell back to sleep now, he'd still get a few more hours of rest in before morning practice. However, that task was not as easy as it had sounded in his head. Especially not when one felt as though they were now wide awake.

Leonardo rolled onto his right side for about the fifth time in the last half hour, trying to find a more comfortable position, but that was no simple feat when you had a bulky shell on your back. Leo had been tossing and turning for the better part of an hour now, but he just couldn't achieve a tranquil enough state for sleep.

At this point, Leo had already kicked most of his covers off, thinking that perhaps the room's temperature may have been contributing to his current case of insomnia, but then, he remembered that he was cold-blooded. Warmth didn't keep him awake. It helped him to sleep.

Rolling onto his carapace and draping one leg over the side of his bed so that his foot just grazed the floor, Leo tucked an arm behind his head and stared at the ceiling. He let out a long sigh, like he was deflating all of the air out of his lungs.

His mind kept telling him that he needed more sleep, but his gut was telling him that something was off.

As much as Leo wanted to stay in bed, he couldn't just ignore his gut. After all, his gut instincts had always been uncannily accurate. Oftentimes, Leo's youngest brother, Michelangelo, had claimed that Leo's stomach was to hunches as Donnie's brain was to big words and Raph's fists were to punching things. That was why whenever Leo said that he didn't have a good feeling about something, Mikey would start wigging out.

Leo pushed himself up so that he was seated on the edge of his bed. He rolled his shoulders and shifted so that his joints popped back into proper alignment before getting to his feet. He then padded to his door and silently slipped out into the hall of the dormitory area.

The first room Leo approached was his immediate younger brother's, Raphael. Leo figured that Raph was the most likely to get himself into trouble, so it seemed only logical to check up on him first. As quietly as possible, Leo pushed the door to Raph's room open just wide enough to poke his head inside and verify that Raph was in his bed. Once he saw that Raph was sleeping soundly, Leo made a swift exit, not wanting to chance having Raph wake up and see him standing there watching him sleep. That would have been extremely awkward and there's no way Raph would react favorably.

The next room Leonardo headed towards was his youngest brother, Michelangelo's bedroom, but Leo didn't need to bother going into the room to see if Mikey was inside. From outside of the door, Leo could hear his baby brother mumbling and chattering merrily in his sleep. Even while slumbering, Mikey couldn't keep quiet or still for more than a few seconds at a time. A small smile passed Leo's lips as he thought about his happy-go-lucky brother's zany antics. No one could ever accuse Mikey of being boring, that much was for sure.

Walking away from Mikey's doorway, Leo tiptoed towards his second youngest brother's room as quietly as he could, knowing that Donatello was the lightest sleeper of his siblings. The last time Leo had seen Donnie, the genius was shutting down all of the equipment in his lab per Leo's orders. Leo had noticed how worn out his younger brother looked and the oldest turtle had decided to mandate an earlier bedtime for the brainy turtle.

It had been a rough evening on all of them. Leo's wicked sore muscles were proof of that.

Due to a most unpleasant run-in with a dozen-plus Footbots while searching for mutagen canisters, the four brothers had opted to shorten their nightly patrol. Luck had not been on their side that night. The band of brothers hadn't located a single container of mutagen and Mikey had hurt his wrist during the fight. Leo, the dutiful leader of the team, had called for a tactical retreat, and, after some initial grumbling from Raph, the four brothers had used a smoke bomb to slip into the sewers and escape the robotic ninjas that had been effectively waxing their shells. Once down in the depths of the sewers, no one – not even belligerent Raphael – had objected to cutting their losses and heading back to the Lair for the night.

Upon their return home, Donnie, not surprisingly, had gone straight to his lab rather than taking the opportunity to go to bed at a decent hour for once. That was when Leo had decided that an intervention of sorts had become necessary and that he had to put his foot down.

Leo knew that Donatello had been burning the candle at both ends as of late, putting in late-night shifts in his lab . . . possibly all-nighters. That was why Donnie had looked so exhausted all day long, and, it was most likely the reason that Donnie's moves had been less-than-stellar during their skirmish with the Footbots. Leo had had to block a blow meant for Donnie at least twice during the battle and Raph had thankfully grabbed Donnie just before the genius was about to accidentally take a swan dive off of a rooftop.

Donnie had definitely been sloppy and distracted during the fight, which could have been disastrous.

 _Well, more disastrous than it already was,_ Leo groaned in his head.

Leonardo had already made a mental note to confront his little brother about his performance after morning practice. Leo would have lectured Donnie about it before going to bed, but Donnie had looked so dead-tired, Leo didn't think he'd be able to stay awake long enough to hear him chew him out.

Slowly pulling down on the handle of Donatello's door and pushing it open with the slightest of movement so as not to be detected, Leo crept inside of Donnie's room to check on his younger brother only to discover that there was no brother to check on. Donnie's bed was unoccupied and showed no visible signs of having been slept in any time recently. The bedding and pillow appeared to be untouched and arranged eerily similar to the last time Leo had been in Donnie's room, which was four or five days ago.

Initially, a flood of panic washed over Leo when he thought back to the bad omen kind of feeling he had gotten in his gut earlier. The feeling that had told him something was wrong. The sudden realization that his second youngest brother was missing sent Leonardo into a momentary tizzy as his sometimes overactive imagination began to sift through the scores of worst case scenarios that popped into his head. Each one was more gruesome than the next. Then, Leo's sensible side took the helm once again and panic was quickly replaced by irritation.

Staring down at Donnie's vacant bed, Leo clenched his fists at his sides and pressed his lips into a thin, grim line. He knew exactly where Donatello was. The very same place Leo had left him in when he had mistakenly assumed that his little brother had listened to him.

Something along the lines of a growl rumbled in the recesses of Leo's throat.

Exiting Donnie's room in far less stealthy fashion than he had entered, Leo marched through the arched stone aperture that lead to the main living space of the Lair and headed straight for Donatello's lab.

Normally, Leonardo would have knocked on the laboratory door, or, at the very least, announced his presence before entering his genius brother's domain, but, in this case, Leo wasn't feeling all that courteous and he skipped such respectful formalities. It was a breach of manners, Leo knew, but he wasn't really concerning himself with such things at the moment.

When Leo stepped foot inside of the lab, it took less than a split-second to spot his younger brother, who was hunched over his desk, pouring something into a beaker. As soon as Leo made his way past the threshold of the lab entrance, Donnie let out a sharp gasp and one of his hands instinctively flew to his chest to make sure his heart was still where it should be. The other hand nearly dropped the test tube he was holding.

Needless to say, Leo had startled Donnie.

"L – Leo! What – what are y – you doing up?" Donnie stammered out in a whiny tone that came out about a half-octave higher than Donnie had wanted. The genius turtle was also vaguely aware of the undesirable tremor that rocked his voice. It was certainly not a confident way to start off what was sure to be an uncomfortable conversation.

"Funny . . . I was about to ask you the same thing," Leo said in a much colder manner than Donnie had expected, which was undoubtedly a bad sign of things to come. Donnie also noticed that Leo approached his desk using far shorter, ungainly strides than was typical of his graceful big brother. He was almost . . . stomping. Kind of like Raph would.

 _This is so not going to bode well_ , Donnie thought to himself.

Placing the test tube he had been holding when Leo had barged into the lab into a test tube rack, Donnie then quickly put his hands under his desk to hide the fact that they were trembling. Once his hands were concealed from Leo's line of sight, Donnie sat in premeditated silence, opting not to respond to Leo's comment so that he could buy himself some time to think. Well, that and every response that popped into Donnie's head was sarcastic in nature and he was fairly certain that Leo was not in the mood for his wit right about now.

Donnie was right. Leo was _so_ not in the mood.

A scowl creased Leonardo's features as he stared at his younger brother, who was intently staring down at the surface of his desk.

It didn't take a scientific genius like Donatello to see that said turtle was doing his best to avoid eye contact with his oldest brother, which only irritated Leo all the more. The least Donnie could do was have the decency to look him in the eye after what he had done.

"Donnie! Do you have any idea what time it is?" Leo asked, folding his arms across his plastron and tapping his foot on the floor impatiently. Again, Leo's behavior was more befitting of Raphael.

 _Apparently, Leo got up on the wrong side of the bed this morning . . ._ Donnie thought to himself, somewhat amused.

Of course, the irony of that thought was not lost on Donatello. The moment Leo had come in, showing clear signs of anger, it had occurred to Donnie that Leo was crabby because he _hadn't_ gone to bed. The paradox would have been hysterical if Leo wasn't so darn grumpy.

The scowl lines on Leo's face deepened as he waited for Donnie to reply to his question. Leo could have sworn he saw the ghost of a smile pass Donnie's lips, but he gave his little brother the benefit of the doubt, thinking there was no way Donnie could have possibly found the situation the least bit humorous.

Then, as if to prove Leo wrong, out came a taste of Donnie's infamous sarcasm.

"Is that question supposed to be rhetorical or do you actually want me to tell you what time it is?" Donnie had not meant for his answer to sound quite so abrasive, but once it left his mouth, it was obviously too late to take it back. Unfortunately, life didn't have an undo button like computers did. Donnie oftentimes found himself wishing that it did. It would have made things so much easier if he could just click a button and wipe out all of the stupid things that he had done in his life.

 _Timothy would still be human . . ._

 _April would still be my friend . . ._

 _My brothers wouldn't think I'm useless . . ._

"It's four o'clock in the morning, Donnie!" Leo howled in the shrill, snarky voice he reserved for when he got really worked up about something. Leo liked to think that he had honed his vocal intonations enough that he could imply 'have you lost your mind?' or 'what were you thinking?' without actually having to say the words.

Dropping his arms to his sides, Leo balled his hands into tight fists as he stooped over Donnie, who was still sitting in his chair, looking down at his desk. Obviously, talking to the top of Donnie's head was not ideal. Leo really wished Donnie would just look at him so he could better gauge what Donnie was feeling right now. Sometimes, Donnie could be difficult to read. Whereas Leo's other two brothers didn't try to hide their emotions – even if Raph's emotions pretty much consisted of anger and more anger – Donnie had a tendency to keep his emotional cards close so no one could see them. Sure, they could visibly see if Donnie was upset about something, but a lot of times, that visual confirmation was all of the details they got out of their introverted brother. Donnie had a bad habit of bottling things up inside. Instead of talking to his family or friends, his solution was to hide away from them in his lab so he could try to work through things on his own.

Hence the reason Donnie was in his lab at this very moment.

Leo was just starting to feel sorry for his little brother when Donnie spoke again.

"Technically, it's closer to four – thirty," Donnie corrected Leo, lifting his head up slightly and pointing at the computer monitor to substantiate the accuracy of his statement. In all actuality, Donnie was only trying to be helpful when he had corrected his brother, but Leo hadn't seen it that way. It was yet another time that Donnie's mild case of OCD had gotten him into trouble.

 _Me and my big mouth . . ._

"Don't get smart with me, Donatello!" Leonardo scolded, planting his hands on his hips to strike one of his classic 'I'm the leader and you're not' poses that had clearly come straight from the playbook of Leo's all-time favorite television character, Captain Ryan, from that extra cheesy Space Heroes cartoon Leo was so infatuated with.

 _Did he seriously just tell me not to get smart with him? Seriously? That's like bringing Mikey to a pizza parlor and asking him not to eat anything._

A hundred and one snide comebacks raced through Donnie's brain at all once, but he had to bite his tongue, hard, in order to keep himself from capitalizing on such an easy opportunity to let his sarcasm run rampant at his oldest brother's expense. Besides, Leo had just employed his full name, which warned Donnie that his older brother was not to be trifled with right now. Leo didn't use their first names unless he really meant business.

Now gnawing on the inside his bottom lip rather than his tongue, Donnie wrapped the hand that he had used to point at his computer just a few seconds ago around his forearm and rubbed his palm up and down his arm nervously. Still purposely attempting to avoid the disapproving stare that Donnie presumed Leo was giving him, Donnie's eyes wandered back down to his desk. That was when his gaze locked onto the beaker three-quarters full of mutagen. That was when his eyes started to gather moisture once again.

He could still hear himself making that oath to Timothy.

" _I promise, Timothy. One day, I'll turn you back."_

He couldn't stop thinking about the vow he made to April.

" _I swear by Darwin's beard we'll cure him."_

He had promised them something that he wasn't even sure he was capable of.

 _Smart one, my shell . . . I'm about as useful as a glass hammer._

Donnie was half-tempted to throw that beaker of mutagen across the room, but he didn't want his brother to bear witness to him lose his temper. Leo was already disappointed enough in him as it was, just like everyone else who had the displeasure of knowing him . . .

He had let Timothy down.

He had let April down.

Now, he had let Leo down.

Was there no end to his incompetence?

Donnie was so caught up in his own misery that he didn't even notice Leo bend down right beside him. At least, not until he felt Leo's hand cup firmly underneath his chin and pull his face up towards him, forcing Donnie to look at him against his will. Donnie immediately tried to break free of Leo's grasp, but then Leo curled his other hand around the back of Donnie's neck to hold his brother in place.

It was at this point that Leo realized what poor health Donnie was truly in and he kicked himself for not noticing it sooner. Donnie's normally bright, beaming ruddy-brown eyes were red-rimmed and duller than Leo ever remembered seeing them. Even with the scant lighting in the lab, Leo could still see the dark circles and bags under Donnie's cloudy eyes. His brother's purple mask could not hide how terrible Donnie looked.

Leo wondered how the heck he could not have seen this before. Yes, Leo had observed that his second youngest brother had looked more tired than usual, but _this_ . . . _This_ was beyond tired. Donnie looked like a shell of his normal self.

 _Surely, Donnie couldn't have looked this bad last night . . . I would have noticed . . ._

Examining Donnie's wilted figure before him, Leo shuddered at the sight of his brother. The skin on Donnie's face was hollowed, sunken, and pale and it felt much warmer than it should. Not only that, but Leo could feel his brother shivering in his grip.

"Donnie . . . when was the last time you got some sleep?" Leo asked with a mixture of concern and frustration as he pulled his brother closer.

Donnie's ashen cheeks flushed with a slight tint of scarlet as he once again tried to pull away from his brother's hold, but Leo did not let up. If anything, he just clutched Donnie tighter, to the point that Donnie was pretty sure it was going to leave marks behind.

"Leo, you're hurting me," Donnie practically whimpered, still futilely attempting to wriggle himself loose.

Leo noticed that Donnie's efforts to get away were feeble at best and he was getting more and more flaccid by the second. Leo had felt more resistance from a blanket.

"Answer the question, Donatello!" Leo barked, not slackening his grip even the slightest bit. Leo hated to be so harsh when his brother was clearly not well, but he had to know the answer.

Donatello's eyes widened to twice the size that they had been moments before and he peered up at Leonardo, nonverbally pleading with his big brother to release him, but Leo didn't budge.

The anger burning inside of Leo was making it difficult for Leo to think straight. At this point, he wasn't even sure who or what he was truly mad at.

"How long, Donnie?" Leo hissed, giving Donnie a vigorous shake.

"I . . . I'm not sure. N – not s – since the night I – I froze Timothy . . . I – I think," Donnie stuttered and he closed his eyes so that he did not have to see Leo's reaction.

"What? That was like five or six nights ago! You haven't slept for almost a week? Why would you do that?" Leo asked and his voice was growing more and more agitated as his stress level rose. He couldn't believe that Donnie would neglect his own personal safety like this. Even worse, Leo couldn't believe that he had neglected Donnie's safety like this. As Donnie's big brother and his leader, it was Leo's responsibility to protect and watch over Donnie. How could he not have seen that Donnie had been abusing himself so badly? How could he have let it go on for so long?

"Leo," Donnie breathed out his brother's name, and then, his voice all but abandoned him before he could go any further with what he had been trying to say. He cursed himself for being so weak.

"And when was the last time you ate something, Donnie? And I mean solid food! Coffee doesn't count!" Leo snarled, not even realizing that he was still shaking his little brother with each syllable that he spoke.

"I . . . I don't know. Maybe . . . a few days? I . . . I was – " Donnie tried to explain, but Leo didn't allow him finish.

"You were what, Donnie? _Trying_ to make yourself sick? By starving yourself? By not getting any sleep?" Leo seethed and his blue eyes narrowed into nothing more than angry slits zeroed in on Donnie.

Donnie cowered away as much as he could, which wasn't much at all. Leo's grip was unfaltering.

"No . . . I . . . I was . . . I had to –" Once again, Leo cut Donnie off before he could complete his sentence. It was a getting to be a rather annoying trend and Donnie could feel his fear edifying into something more aggressive than what he was used to feeling.

"You didn't _have_ to do anything other than go to bed, which I told you to do hours ago, but you _chose_ to disobey me!" Leo snorted, putting heavy emphasis on the words 'have' and 'chose.' Donnie could see and hear that Leo was clearly upset, but, then again, so was he.

"I couldn't just drop what I was doing, Leo! I had work to finish!" Donnie snorted back, taking Leo somewhat by surprise.

"Work that could have waited until morning! You completely disregarded my orders, Donatello! I thought I could trust you, but apparently not," Leo uttered, fully intending for the words to cause offense. With that said, he finally released his hold on Donnie's chin, but only so that he could pull his T-phone out of his belt. As Leo started to push buttons on his phone, his other hand remained tightly clamped around Donnie's neck, effectively keeping him pinned down in his chair.

"Wait! Wh – what are you doing?" Donnie asked with anxiety filling his voice. His moment of anger had subsided and he was now trying frantically to free his neck from Leo's iron grasp to see the screen image on his oldest brother's T-phone, but Leo used his better leverage point to keep Donnie trapped in his chair while he sent off a quick text message.

"Sorry, Donnie, but you left me no other choice. Raph will be here soon," Leo said, tucking his T-phone back into his belt.

"What? You texted Raph? At four o'clock in the morning? Are you insane?" Donnie shrieked, his voice nearing soprano range. If circumstances were a little different, Leo might have laughed at Donnie's high-pitched voice.

"Well . . . technically, it's closer to four – thirty, remember?" Leo said with a bitter smirk, throwing Donnie's prior smart-aleck response back in the genius's face without an ounce of sympathy.

"You're out of your shell! Do you even realize what you've done? Raph is gonna de-shell us both for waking him up!" Donnie snapped, struggling to keep his volume down to a 'non-wake up the entire Lair' level.

Knowing exactly what he had done, Leo continued to hold a now very-panicked Donnie against his will until a very-irate Raphael came trudging into the lab, much like a raging bull entering a fighting ring. It was painfully obvious that Raph had just woken up and it was even more painfully obvious that Raph was not a happy turtle. Not at all . . .

Donnie gulped down the lump stuck in his throat, loudly. Leo gulped as well, only he was a little more subtle about it.

"I got your text, Leo. Someone better have a darn good reason for waking me up," Raph growled in a gruff voice as he tilted and turned his head from side to side to audibly crack his neck. Raph liked to use neck cracking as an intimidation tactic of sorts. He wanted to be sure that his brothers understood that they had seriously teed him off when they had decided to interrupt him from what had been a really pleasant dream.

"Oh, it's good, all right. I just found out that Donnie hasn't slept for five or six days, Raph. Not since the Timothy incident," Leo announced, fully aware that he had just tattled on his second youngest brother like they were little kids again. Leo wasn't exactly proud of that fact, but Donnie's health came before his pride. Leo knew that Raph would have an easier time getting Donnie to go straight to bed than he would. Sure, that's because Raph would throw Donnie over his shoulder or drag him kicking and screaming, but at least Donnie would get some sleep. Well, after he calmed down.

"You what?" Raph grunted, fixing a livid glare at Donnie, who was now visibly shaking all over. Leo wasn't sure if that was because Donnie was sick or because he was frightened of Raph. "When I said you looked tired and asked if you were okay yesterday, you said you were fine! You lied to me!" Raph thundered, pointing a foreboding finger at Donnie.

"I – I wasn't lying! I _was_ fine! I _am_ fine! You two are totally overreacting. Now, will you please just leave me alone so I can finish up my work before practice?" Donnie asked almost mockingly and he had observed that as he was making his request for his older siblings to leave, Leo had backed away to give Raph full access to him. Donnie looked up at Leo as though he was a traitor for doing so. In a way, Leo was. It was kind of like he was handing Donnie over to the enemy.

"Oh, don't think you're getting off that easy, Brainiac! You brought this on yourself!" Raph roared menacingly, cracking his knuckles. "You're going to bed, now! You know the routine. And I suggest you cooperate and keep quiet this time. You don't want to go waking up Master Splinter again, do you?" Raph asked snidely, following with a crooked sneer.

"No! Don't touch me!" Donnie shouted, pushing himself up out of his chair and holding his hands out to defend himself from Raph's advances.

Unbeknownst to everyone in the lab at the time, Donnie getting up so fast was a mistake. A really, _really_ big mistake.

" _Donnie . . . "_

As soon as Donnie stood up, the edges of his vision started to soften and everything around him started to get all white and fuzzy, like his brain was using a blurring effect from some kind of photo editing software. Then, all of the sudden, Donnie's head felt as though it was a balloon floating high above him and his skin started to tingle and go numb.

" _Donnie? Donnie!"_

Confused by what was happening to him, Donnie looked to his brothers for answers, but he could barely see them through his now spotted and distorted eyesight. It was at that point that he realized his hearing was no longer working the way it should be, either. He could hear that his brothers were speaking in what sounded like panicked tones, but everything they were saying was a jumbled up mess, completely incomprehensible, as if they had switched languages when he knew they hadn't. Raph didn't even know a second language. Not unless cussing was considered a language.

" _Donatello!"_

As his brothers' voices began to fade into nonexistence, what Donnie could still see through his hazy eyes started to spin relentlessly and Donnie could feel his breathing start to catch in his chest, as if his lungs were shutting down on him. Scared out of his shell, Donnie was about to call out for help when his world rapidly went black and he felt his legs give out underneath him. And then . . . there was nothing.

* * *

 _ **To be continued . . .**_


	2. Chapter 2 - The Weight of the World

_***Disclaimer: I do not own the rights to the Teenage Mutant Ninja Turtles franchise.**_

 ** _*Author's Note: Here's the second chapter of 'A Shell of Himself.' Thank you so much to everyone for reading, 'favoriting,' following, and reviewing this story as well as 'You're Needed Here Now, Donnie.' I really, really appreciate it._**

* * *

 **Chapter 2 – The Weight of the World on His Shell**

It took a while for his eyes to adjust to the light, but after blinking his heavy eyelids a few dozen more times to help him adapt to the soft glow of the space he was in, Donatello's brown orbs had focused enough to see that he was in his bedroom surrounded by his brothers and his father.

This confused him more than anything.

"Dudes, he's awake!" A familiar voice rang out and Donnie instantly recognized it as his youngest brother's.

Donnie peered up at his family through his half-mast eyes and felt a wave of dread wash over him. Why were they all in his room? And more importantly, why were they all hovering over him and staring at him like that? And how did he wind up in his bed anyway?

Donnie tried to sit up, but four pairs of hands pushed him down to his bed.

"Whoa . . . You need to lie still, Donnie," Leo said in a no-nonsense tone.

"Wha . . . what happened?" Donnie rasped weakly, trying to visually assess the situation from his prone position. He still couldn't remember how he had gotten here. The last thing he lucidly recalled was being in the lab with Leo and Raph. He remembered getting up off of his chair and then . . .

"You passed out and just about cracked your skull wide open, you idiot," Raph said a little more bluntly than he had meant to, earning him a stern glance from Master Splinter.

 _And the award for least likely to be the favorite child goes to . . ._

"Raph caught you just before you hit your head on the edge of your desk," Leo said and though his expression was that of relief, Donnie could see that his oldest brother was undeniably holding something back. If Donnie had to venture a guess, he would say it was anger and he had no doubt in his mind who Leo was angry with.

"You were like totally out of it, bro! You wouldn't even wake up when I dumped coffee all over you," Mikey added.

"Why would you dump coffee on me?" Donnie asked irritably, checking himself over for coffee stains.

"'Cause coffee's supposed to wake you up. That's what coffee's for. It's not like people drink the stuff 'cause it tastes good," Mikey answered, using that distinctive 'duh' tone that he liked to use whenever he thought the answer should have been a no-brainer to everyone and their mother when most of the time what he was saying didn't make any sense. "Besides, it wasn't like it was hot and I cleaned it up for you," Mikey said as if he expected praise for his astonishing efforts, but all he received for his troubles were simultaneous eye rolls from everyone else in the room.

"Yeah, with some of Donnie's textbook pages," Raph said in a deadpan way that made it impossible to tell if he was being serious or not.

"What?" Donnie yelped, assuming the worst of Mikey. After all, that _was_ usually the case.

"Chillax, D! I didn't use your textbooks," Mikey said, holding his hands out to calm Donnie down. Mikey then went on to say, "The books I used had pictures in them."

"Textbooks can have pictures in them, you dork!" Raph barked, crossing his arms in a huff.

"For reals? Oh man . . . " Mikey whimpered and then let out a nervous little chuckle as he rubbed his bandaged wrist.

"Mikey!" Donnie shouted and immediately regretted the decision to raise his voice. He was agonizingly reminded that he still had a massive headache. "Ugh . . . How long was I unconscious?" Donnie asked, wincing as he wrapped a hand over the top of his throbbing head.

"Like twenty of the longest minutes in history, dude! You just about gave us all a heart attack, bro!" Mikey practically screamed, flailing his arms about for dramatic effect. Apparently, his wrist injury wasn't as bad as he had led on.

Donnie again winced at the heightened noise level.

"Donatello, how are you feeling?" Master Splinter asked, having observed his second youngest son's signs of discomfort.

"I . . . I feel fine, Sensei," Donatello answered and he saw Leo and Raph both tense at the response. Donnie knew an unforgettable butt chewing was imminent.

Raph was the first to voice – or more like growl – his opinion.

"You are not fine, Donnie! You fainted because you were too – " Raph stopped himself midsentence to keep from saying 'stupid,' which he knew his father would never approve of. Raph instead opted to go with something slightly less insulting and hoped that no one would notice the awkward pause for thought. " – _stubborn_ to take care of yourself!"

"It's not very often that I say this, but Raph's right, Donnie. You're definitely not fine. What you did was foolish and extremely detrimental to your health," Leo stated in all seriousness and his voice was void of any warmth or compassion. It was as if Leo had found a switch to shut off all of his emotions. Strangely, Leo was starting to sound more and more like Master Splinter with each passing day.

"Not to mention Mikey's health. He was freaking out the entire time you were unconscious. You should have heard him crying," Raph said, giving Mikey a somewhat gentle elbow to the plastron.

"I didn't cry . . . much!" Mikey declared and began to sulk, jutting out his bottom lip in a classic Mikey pouty face, much to Raphael's amusement. Raph then hooked an arm around Mikey's neck and playfully rubbed his knuckles against his baby brother's head, and, soon, Mikey's big, goofy grin was back.

The somber mood lightened, but only for a fleeting moment.

A small, thin voice then captured all of their attention. "I'm sorry for worrying all of you," Donnie muttered with a heavy pang of guilt, dejectedly casting his eyes away from his family.

An awkward hush fell over the room until Leo's placid voice cut through the reticence.

"Guys, if it's okay with you, I would like to talk to Donnie alone . . . about what we discussed earlier," Leo said, bouncing his gaze from Master Splinter, to Mikey, to Raph, and then back to Master Splinter again, awaiting their approval to move forward with his proposal.

As brilliant as Donnie was, he could sometimes miss the obvious, but not in this case. Based on Leo's vocal nuances and what his oldest brother had just said, Donnie sensed there was trouble on the horizon. He turned his eyes back towards his family members and it was evident that they were up to something. Donnie's eyes then zoomed in on Mikey, who had always been the easiest to read of the bunch, and, judging by Mikey's apprehensive reaction, whatever they had in store, Donnie wasn't going to like it much.

"What's going on? What are you guys not telling me?" Donnie asked, narrowing his eyes skeptically as his stomach acids started to churn with trepidation.

"I think Leo's about to give you the most epic lecture ever. Sorry, bro," Mikey said, patting Donnie on the shoulder sympathetically. If it would have been anyone but Mikey, the gesture would have been rather demeaning, but Donnie knew that Mikey really did feel sorry for him.

"I still think I should be the one who gets to lecture him. He's a lot more scared of me than he is of you, Fearless," Raph said, pounding a fist into his open palm to stress his point.

Seeing Raph's hostile gesture made Donnie shrink a little deeper into his pillow and he pulled his blanket up to his chin as if the fabric could act as some sort of shield against Raph.

"Hey! What about me? Who talks more than I do? I could totally lecture his shell off!" Mikey chimed in, more excited about the idea than he probably should have been. His bright blue eyes gleamed with anticipation and he nodded his head like he was a bobble head doll.

"We're talking about lecturing him, not torturing him, Mikey. You know, come to think of it, maybe Leo _should_ be the one to do it. Who better to bore Donnie to sleep than Leo? Well, other than Donnie himself . . . " Raph teased and his lips curled into a twisted grin as his green eyes leered at Leo and Donnie.

"Real nice, Raph. You know, if we did let you do it, you'd probably terrify him so bad that he'd never be able to sleep again. I think you'd better leave this to me, like we planned," Leo said with an air of arrogance that had Raph itching to smack the green off of him.

"My sons, I believe Donatello needs his rest. Perhaps this is not the best time for the three of you to stand here and argue," Master Splinter diplomatically interjected, trying to serve as the voice of reason that his sons didn't always hear. As he perused his sons' various reactions, he twisted at his long white beard in contemplation.

"Thank you, Sensei. It's nice to know that someone in this family isn't looking forward to lecturing me," Donatello said with a small, innocent smile that made him look several years younger than just moments before.

"I never said that, Donatello. I just meant that there will be plenty of time for the rest of us to lecture you for your foolish behavior when it is our shift," Master Splinter said, straying from his usual detached tone to take on a cynical one. Donnie even saw his father wink as he clasped his hands behind his back and turned to leave the room. Just before he walked out, Master Splinter wryly added, "Sleep well, my son."

"Wait! Shift? What do you mean shift?" Donnie called out to Master Splinter, but his father just kept right on walking as if Donnie hadn't said anything. Donnie could only helplessly watch on as his father silently exited his bedroom.

Now feeling an overwhelming sense of alarm, Donnie glanced back and forth between each of his brothers with his big, curious eyes pleading for more information.

Donnie saw Mikey's mouth form an "O" shape, like he was just about to say something, but he then hastily backed out of the room without so much as a peep, moving in true ninja fashion. Either that or he was moving in true cowardly fashion, because Mikey was too afraid to stand up to his older brothers . . .

With Mikey's swift departure, any chance of Donnie being rescued from his unknown fate went right out the door along with Mikey. Sure, Donnie could have looked to Raph for salvation or mercy, but that would be like trying to squeeze water from a rock. Donnie was more likely to get a hatchday card personally picked out and signed by the Shredder himself than he was to get pity from Raph.

"Well, Fearless, I guess he's all yours. You two have fun," Raph scoffed with an evil smirk plastered on his face as he strolled out of the room, slamming the door shut behind him.

Once the door was closed, it felt like the air in the room instantly got heavier, making the atmosphere even more uncomfortable that it already was. Donnie swallowed thickly and ran his tongue over his lips to moisten them. His mouth and throat suddenly felt as if they had gone bone dry from the rising heat in the room. Donnie could have sworn the room's temperature had already climbed up several degrees since Raph had left just a few seconds ago.

 _Maybe that's because Leo's about to go nuclear_ , Donnie thought grimly as he continued to anxiously await his punishment.

Leo's muscular form wordlessly loomed over Donnie like an ominous, dark storm cloud. It felt like an eternity passed by, but, in all reality, it was only a minute at most. As Leo stood over his bed presumably frowning upon him, Donnie stared down at the blanket he was twisting with his fingers. Donnie figured if he steered clear of making eye contact with his big brother, he might be able to prolong the inevitable just a little bit longer.

After sucking in a noisy breath which Donnie took to mean that Leo was exasperated, Leo pulled up a chair and sat down next to Donnie's bedside.

Still, Leo did not speak and Leo's sudden penchant for silence was driving Donnie crazy. Donnie couldn't take it anymore. Turning his head towards Leo, Donnie finally looked his oldest brother in the eyes and he could see that his brother was waging some sort of internal conflict that was no doubt keeping him from saying what he wanted to say. Donnie was all too familiar with how inner battles felt, so he tried to be of some assistance.

"Look, Leo . . . Let me spare you the lecture. I know what I did was incredibly stupid and I'm sorry for – " Donnie started, but Leo went right back to the whole cutting Donnie off before he could finish thing. Donnie really hoped this new impolite habit of Leo's wasn't going to become permanent.

"This isn't about a lecture, Donnie. This is about your wellbeing," Leo said, slouching forward slightly and resting his forearms on his knees. He was having a tough time finding the words, knowing what he was about to say was going to upset Donnie. Leo had always despised playing the role of the bad guy, but sometimes being the leader and the oldest brother meant that you had to make hard choices. Choices that weren't well-received.

"You don't seem to think that taking care of yourself is important, so we have no other option than to do something drastic to teach you how important your safety is. Not just to you, but to us, as well. You can't expect us to stand idly by and let you keep making yourself sick like this. There has to be consequences for your actions. That's why we came to the decision that for the next five days, you are confined to your room," Leo said, straightening up his posture to ready himself for Donnie's impending temper tantrum. Donnie was never one to resign to his penance.

 _Wait for it . . ._

"Five days? Are you kidding me?" Donnie wailed, instantly pushing himself up into a sitting position on his bed so that he was in a better position to argue the prison term that had just been handed down to him. Donnie's head was the first to dispute his unwise decision to get up so abruptly. Then, it was Leo's turn to object. The eldest brother swiftly sprung out of his chair and firmly yet carefully forced Donnie back down onto the bed. Once Donnie was lying down again, Leo sat on the bed beside his younger brother.

"I'm serious, Donnie. You need to rest, whether you like it or not. You are hereby grounded for one hundred twenty hours, effective immediately. That means no projects, no experiments, no computers, no inventions, and no TV. You are to remain in this room at all times," Leo said, intersecting his arms across his chest and putting on his most formidable expression to illustrate that he wasn't about to waver on this verdict. His mind had been made up on the matter while Donnie had been lying there unconscious from lack of sustenance and sleep. Seeing his little brother in such a debilitated state had sort of put things into perspective for Leo. Sometimes, tough love was the only alternative.

"Grounded? What am I? Four years old? You can't do this! This is totally unfair!" Donnie howled much loader than Leo had expected from his weary brother. Considering that Donnie had just come to after passing out from exhaustion, he sure had more than enough energy to holler at Leo. Power napping just took on a whole new meaning for Leo.

"See! I told you he was totally going to wig out about it!" Came a boisterous voice from the other side of the door.

"Mikey, we can hear you," Leo growled over his shoulder, glaring at the door, not at all amused by his baby brother's pitiful attempt at eavesdropping.

Then, there was a slapping sound, followed by a blaring, "Owwwwww!"

"Can't you ever keep your big mouth shut, shellbrain?" Came a much deeper voice from the other side of the door.

"If you two don't get away from that door right now, I'll tell Master Splinter what really happened to his last two cheesicles," Leo spoke in what seemed like an even voice, but they could all hear the underlying acidity corroding Leo's every word.

"You . . . you wouldn't," was Mikey's petrified reply.

"I would," Leo said in a far creepier manner than anyone would have thought possible from the moralistic, goody-goody leader of the team. The voice sounded as though it had come straight from a chilling horror scene. The spooky shtick seemed to have paid off, because Leo could hear Raph's grumbling and Mikey's whimpering trail off as Mikey was hauled away from the door by a very disgusted Raphael.

Leo couldn't help but to smirk over his accomplishment. He had been waiting all week for just the right opportunity to present itself so that he could play the coveted cheesicle card. The best part was, until his two brothers could muster up the intestinal fortitude to tell Master Splinter the truth about what they had done, Leo would get to play that card to his heart's content.

"Now, where were we? Oh yeah . . . We were going over the terms of your confinement," Leo said nonchalantly, turning back towards Donnie only to see that Donnie was now glaring up at him as though Leo was his most loathed enemy. Leo was just grateful that looks could not take a life or he would have been a goner. Of course, Leo was used to being on the receiving end of such death glares from his younger siblings. As the 'nosiest, bossiest, naggiest' brother (as Raph had so kindly pointed out on a regular basis) and the designated leader of the team, Leo knew all too well that dirty looks kind of came with the territory. Especially when one of your brothers was a hotheaded, argumentative, violent, impetuous, egotistical rebel without a conscience . . .

Still, even with all of Raph's many, many, _many_ faults, Leo would rather argue with Raph than Donnie on any given day. Arguing with Donnie was much more . . . complicated.

"Oh, come on, Donnie. Let's be reasonable about this," Leo said, trying to take a levelheaded approach to the situation, but Donnie wasn't having any of it.

"How is banishing to me to my room for five days reasonable, Leo?" Donnie snapped, attempting to push himself up again, but this time, it was his pounding head that wouldn't let him sit up, not Leo. Donnie collapsed back down to his pillow, trying to work through the overpowering surge of dizziness, nausea, and pain without sounding off any of Leo's built-in big brother alarms, but he failed miserably. Leo saw right through Donnie's ruse.

"You see! This is exactly why we're doing this! You can't even sit up, Donnie. You haven't slept for days and you don't even know when you last ate. You passed out and scared us all half to death. Obviously, we need to take matters into our own hands and take care of you since you refuse to do it yourself. You needlessly put yourself in danger and you – "

Now, it was Donnie's turn to interrupt Leo.

"Needlessly? You think my work is needless?" Donnie bayed, on the verge of shoving Leo off of the bed. He probably would have done so if he wasn't so wiped out.

"No! Of course not! That's not what I meant, Donnie," Leo said, reaching out to wrap his hand around Donnie's, but Donnie yanked his hand away as though it had been scalded by Leo's touch. Donnie then sullenly turned his face as far away from Leo as he could and stared at the wall.

Leo rolled his eyes towards the ceiling and bit back a growl. Sometimes, when Donnie got excessively tired, he could be a regular pain in the shell to deal with. In fact, Leo would even go as far as to say that Raph and Mikey combined couldn't hold a candle to how stubborn Donnie could get when was overly exhausted like he was right now, and that was saying a lot.

"Donnie, look at me," Leo groaned, getting a little frustrated with Donnie's pigheadedness.

"Look, Leo . . . If you want me to stay cooped up in here to appease you, fine! But don't expect me to be happy about it. Now, if you don't mind, I'm going to try to get some rest, since I'm not being permitted to do anything else," Donnie said coldly as he pulled up his covers and turned onto his side so that his carapace was facing Leo. He tried to bury his face into his pillow as deep as possible so that Leo couldn't see the tears brewing in his eyes.

Leo let out a long sigh to steady himself before speaking. He didn't want Donnie to hear his irritation in his voice.

"Donnie, I know what you were working on in the lab and I know how important it is to you, but you can't sacrifice yourself for a cure. I won't let you," Leo said, gently placing his hand on the bumpy surface of his little brother's carapace. Leo wasn't sure if Donnie could actually tell if his hand was there, but he kept it there just the same. A part of Leo was doing it for his own selfish comfort. Leo hated it when any of his brothers were suffering and the physical contact brought Leo a peculiar modicum of relief.

Apparently, Donnie was aware of Leo's hand, because he tried to shrug it off, but his efforts to do so were minimal. He was either too tired to exert any more energy or he didn't want to pull his face out of hiding.

"I don't want to talk about it, Leo. If you want me to sleep, then just let me be. I promise I won't go anywhere without _your authorization_ ," Donnie mumbled into his pillowcase. The words 'your authorization' were spit out of Donnie's mouth as if they were poisonous, intending to sting, and sting they did, but Leo stood his ground.

"I'm not going anywhere, Donnie, because I know the second I turn my back, you'll start working again. That's why we all agreed to take shifts watching you," Leo said with an unlikely blend of strictness and tenderness.

"Oh, so now you don't trust me?" Donnie asked with a muffled voice.

Leo noticed that Donnie was pushing his face deeper into his pillow than before and the younger turtle's knuckles were practically white from clenching his blanket so tight. Leo began to wonder if Donnie's behavior was from actual anger or if it was from an altogether different emotion that Donnie was trying to keep locked up inside.

"I trust you with my life, Donatello, but for that very same reason, I'm afraid to leave you alone, knowing that you are dead set on giving your life for the sake of others. Even for people you barely know . . . You may not care about your safety, Donnie, but I do. More than anything. I would do anything to keep you safe, Donatello, and I'll be shelled if I'm going to sit by and watch you harm yourself for some cure you may not ever be able to create," Leo said and no sooner had the words parted his lips than he regretted them. His younger brother's self-esteem was already fragile enough as it was. Leo certainly didn't need to go feeding into Donnie's ever-mounting insecurities like he just had.

Slowly lifting his head, Donnie turned towards his oldest brother and gave Leo the sad, puppy dog eyes, which filled Leo with unspeakable remorse. There was nothing more heartbreaking than staring into Donnie's big, sorrowful brown eyes, except for maybe staring into Mikey's big, sorrowful blue eyes. The two youngest turtles had the tragic eyes thing down to an art.

"Donnie, I . . . I didn't mean that I don't believe you can develop a cure," Leo clarified, hoping to repair the damage he had just done by implying that his brother was incapable of finding a cure. That was last thing Donnie needed to hear right now. Especially coming from his big brother.

Unfortunately for Leo, Donnie had always been hypersensitive to criticism and he took things much more personally than the average person or turtle. Donnie's pure and gentle heart was easily broken and Leo's thoughtless insinuation had done just that.

"It's okay, Leo. You can say it. I know that everyone thinks I'm nothing but a useless failure," Donnie said, averting his eyes from Leo once more, taking the opportunity to stare at the wall again. Donnie was now gripping the blanket so tightly, it was a wonder that he hadn't torn it to shreds.

It was at this point that Leo's concern for his brother increased tenfold. Leo had already seen a glimpse of the grief residing in Donnie's eyes moments before, but Leo now knew that his brother had been concealing something that went much, much deeper than simply finding a cure for Timothy and Mr. O'Neil.

"That's not true, Donnie! No one thinks that," Leo soundly countered, twisting his lean body so that he could plant a hand down on the bed on the opposite side of Donnie that Leo was currently sitting next to. This maneuver not only allowed Leo the ability to lean in closer to his younger brother, but it also effectively kept Donnie trapped on the mattress in the event that the shy and withdrawn turtle had any ingenious plans of trying to flee the room in order to elude the emotionally charged subject matter that he had just inadvertently drudged up.

"Well, you should," Donnie breathed out, pausing briefly to collect himself before continuing. "It seems like the only thing I'm good at these days is screwing up. Everything I do just ends in disaster," Donnie muttered, swathing his arms around himself in a futile attempt to console himself. At the same time, he was also trying to make himself as small as possible so that he might just disappear. With Leo now suspended over him, Donnie felt totally exposed and he was suddenly feeling as though he was going to come apart at the seams at any second.

"Why would you think that?" Leo asked in a demanding yet tender tone, inching closer to Donnie, trying to get his brother to look him in the eyes.

"Think about it, Leo. Ever since Master Splinter allowed us to go up to the surface, I've done nothing but mess things up. I let Baxter Stockman get a hold of the T-pod and he nearly crushed us. I used advanced Kraang technology I knew nothing about to design Metalhead and it wound up just about killing all of us. When the whole Metalhead thing didn't work out, I invented that laser-guided missile launching staff that nearly blew up the Lair, with us in it. My poor planning and fighting abilities got Mikey and I captured by Dogpound, and, if not for you and Raph, we would have been toast. I crashed the Shellraiser through a wall, which caused us to lose the Kraang powercell. I broke into a Kraang detention facility to rescue April's dad, only to release a deadly mutant in the process and lock Mr. O'Neil and I up in a cell so you guys had to come break _us_ out. To make matters worse, I didn't realize that the Kraang had implanted a mind-control device on Mr. O'Neil's neck and I lead him right to April. She was captured because of me. And, speaking of April, let's not forget how my stupidity caused dozens of mutagen canisters to fall onto the city, including the canister that mutated April's father. I caused Mr. O'Neil to get mutated, just like I caused Timothy to get mutated. Some ninja I am. I should have been quicker. . . Better . . . I should have saved them. Now, Timothy and Mr. O'Neil may never be human again, all because I'm too incompetent to formulate a retromutagen. And April . . . she's never going to speak to us again because of me. It's . . . it's all my fault. I wish . . . I wish I had never gone to the surface," Donnie said, sealing his eyes tightly shut to hide the hurt and the tears that he was struggling to hold back. Inside, he felt as though he was about to completely fall to pieces, but he couldn't let his oldest brother bear witness to such a demonstration of frailty. Leonardo had always been all about honor, dignity, and bravery and Donnie knew that there was no honor, dignity, or bravery in bawling like a baby, which was what he really felt like doing right about now.

 _Maybe if I just pretend like I fell asleep, Leo will forget about this whole thing_ , Donnie thought, but then he remembered that Leonardo never forgot about anything . . . _ever_! Oh how Donnie just wanted Leo to leave the room right now. That way, Donnie wouldn't have an audience to see him break down.

"Leo, please go. I just want to be alone," Donnie practically begged, keeping his eyes closed as he cranked his head to the side and pushed his face into his pillow once more.

As he watched his little brother burrow his head into the stuffing of his pillow yet again, Leo gritted his teeth and pressed his lips into a thin line, trying to rein in his fury. He wasn't furious with Donnie – not in the slightest – but rather he was furious over what April had done to his genius little brother to get him this depressed. Leonardo still remembered the last thing April had said to them, just after she had found out that they were responsible for her father's mutation.

" _Don't! Don't touch me! You keep away from me! I never want to see your faces ever again!"_

The words in the statement had been geared towards all four brothers, but Leo had noticed how April had looked right at Donnie as she had said it, glaring at the genius turtle like she was trying to reduce him to nothing but ashes with her eyes. The shattered look on Donnie's face had been hard enough to take, but what really made Leo furious was that April had known perfectly well that Donnie would take what she had said the hardest, but she had said it directly to him regardless. It was as though she had wanted to deliberately hurt Donnie the most, and, for that, Leo was not sure if he could ever forgive April. Sure, Leo realized that April had been extremely upset by the disturbing news that Mikey had so heedlessly unloaded on her about who was to blame for her father's transformation, but in Leo's eyes, that didn't give her the right to take her anger out on Donnie of all turtles. April was fully aware of how deeply Donnie cared for her and she had used that against Donnie to hurt him, badly. Leo found her actions inexcusable. That was because Leo couldn't tolerate anyone hurting one of his little brothers like that. Not even April.

Any fool could see that Donnie hadn't been himself since April had walked out of their lives and it had been getting progressively worse with each passing day. Leo would be lying if he said that Donnie's recent behavior wasn't scaring him. The past couple of weeks, Donnie had been keeping to himself far more than usual, isolating himself in his lab all hours of the day and night. When Donnie did come out, he was unnervingly quiet and distant, moping around the Lair like every last trace of happiness had been sucked out of him.

Then, on top of losing April and everything else, Donnie had lost Timothy as well. That's when Donnie pretty much stopped coming out of the lab altogether other than for practice and patrol. That was when Leo should have stepped in, but he hadn't. Thus, the reason Donnie had worked himself until he literally dropped, and, thus, the reason Donnie was in such a despondent state.

Leo had failed Donnie as a leader and as a brother. He had seen the signs, but he had not acted upon them.

Leo still remembered when Donnie had told them why he thought Timothy was going after April.

" _I didn't know it, but I think all of my April talk made Timothy go after her."_

" _You told your thoughts and feelings to a pile of guts in a jar!"_

" _He's a good listener!"_

In hindsight, that revelation from Donnie should have alerted Leo that his brainy little brother desperately needed someone . . . anyone to notice him. It had essentially been a cry for help that had gone unanswered. After all, Donnie had divulged to them that he had been sharing his innermost feelings with an unintelligent, gelatinous blob he hardly knew (even when that blob was a human). While Mikey and Raph had found Donnie's admission creepy, Leo had found it utterly heartbreaking. It pained Leo to realize that Donnie didn't feel comfortable enough to talk to his own brothers about his feelings. It meant that, all this time, when Donnie had been feeling sad or alone, he didn't think he had anyone to turn to other than a mutant in a glass jar in his lab.

Instead of asking his family for help, Donnie had shut them out and they had just let him do so.

Now, here they were, weeks later, and Donnie was hurting even more so than the night April had basically unfriended them, which, up until now, Leo would have thought was physically impossible. Leo had never thought Donnie could have been more distraught than the day that April had told him that she never wanted to see them (him) again, but Leo was wrong. The Donnie before him right now was much worse.

Without Timothy, Donnie had in essence emotionally shutdown and focused all of his attention and efforts on finding a cure, because he wasn't equipped to deal with all of the emotions running rampantly through him on his own. That was why he had locked himself away in his lab for days. That was why he had stopped eating. That was why he had abstained from sleeping. That was why he hadn't been taking care of himself. It wasn't because he was being careless or selfish . . . or even foolish. It was because Donnie was broken inside and he didn't know what else to do other than to try to fix things. That was what Donnie had always done. He fixed things and when he couldn't fix things, he fell apart. It was killing Leo inside to know that Donnie had been suffering in silence all this time, thinking he had lost his only friends. All this time, Donnie had thought he was all alone.

But Donnie was never alone and he never would be as long as he had his family. It was now up to Leo to make his little brother see that.

Leo ever-so gently cupped Donnie's face in his hands and turned Donnie's head so that the two of them were face to face. Donnie's eyes remained closed, but that didn't dissuade Leo any.

"Donnie, if you would have never gone to the surface, April and her father would both be prisoners of the Kraang. Have you forgotten how you rescued April from the Kraang . . . and ultimately, you were the one who rescued Mr. O'Neil as well?" Leo asked with his patented benevolent big brother tone that always had an inexplicable way of making Donnie's defenses melt away.

Donnie's bottom lip started to quiver, but that was his only outward response. He was fighting tooth and shell not to give into Leo's subterfuge.

"And none of those other things you listed off were your fault, Donnie. Well, maybe the missile launcher was, but the rest of them weren't. Yes, you created Metalhead, and, yes, he tried to kill us – " Leo flinched when he it dawned on him that what he had just said may well have done more harm than good to Donnie's already crippled psyche, but Leo was quick to put a positive spin on what he was trying to say. " – but Metalhead helped stop the Kraang from dumping mutagen into the city's water supply. Your brilliant invention was the key to saving the people of New York."

Donnie sniffled softly and he felt a solitary tear roll down his cheek. That single drop managed to sneak past his mask, somehow defying the laws of gravity and drifting towards Leo's hand. Donnie just prayed that Leo hadn't seen it, but when Donnie pried his eyelids open, he discovered that Leo's face was only about a foot above him. He knew there was no way Leo could have possibly missed it.

Embarrassed beyond belief, Donnie lifted a hand to wipe away the obvious sign of weakness running down his cheek, but Leo beat him to it, using his thumb to sweep away the dampness with a downy soft touch that made Donnie nearly lose his composure right then and there.

"As for the T-pod incident, getting captured by Dogpound, rescuing April's dad, losing the mutagen canisters, and what happened to Timothy, I'm pretty sure you weren't the _only_ one at fault in any of those instances. You may have been the one who created the T-pod, but Mikey was the one who lost it, not you, remember? And I know that getting captured by Dogpound wasn't entirely your fault. Part of the reason you and Mikey were captured by Dogpound was because of the whole A team/B team thing that Raph and I had started. The four of us should have gone after Dogpound together, not divided like we did. And speaking of not doing things together, the whole reason you went after April's dad on your own was because of Raph, if I remember right. Raph is totally to blame for that one. And don't even think about taking the blame for not knowing that Mr. O'Neil was being mind-controlled. None of us saw that one, Donnie. Not even April. There was no way you could have known it was a trap. And the mutagen canisters ordeal was _definitely_ not your doing. Again, I seem to recall Mikey being mostly responsible for that catastrophe. You were the one who tried to stop it, Donnie. Despite what Raph said to you afterwards."

In the back of his mind, Leo could still hear what Raph had callously said to Donnie and Mikey after the mutagen canisters fell from the Kraang stealth ship.

" _All that mutagen! You two are the biggest screw ups ever!"_

The second Raph had made that comment, Leo had wanted to give his ill-tempered brother a beat down, but they were up to their shells in trouble at the time. In retrospect, Leo realized that he should have immediately pointed out to Donnie how wrong Raph was for saying what he had. While it might not have softened the blow of April later cutting all ties to their relationship, it may have made Donnie less likely to push all of them away if he didn't believe that they thought he was one of 'the biggest screw ups ever.'

 _Stupid Raph_ . . . Leo mentally groaned.

"And the Timothy thing was certainly not your fault, Donnie. Not for a second," Leo reassured Donnie with all of the conviction he could summon. Leo felt Donnie shudder in his hands, clearly shaken by the thought of Timothy.

Leo remembered that Donnie had been the only one who had truly tried to save Timothy.

" _Pulverizer, do yourself a favor and quit the Foot."_

From the moment the four brothers had met the clumsy ninja/superhero wannabe, 'the Pulverizer,' Donnie had been the one turtle who had had Timothy's best interests at heart. Donnie had felt sorry for the boy and he had adamantly been against Timothy spying on the Foot from the start. Leo could still recollect the verbal exchange between Donnie and Raph about 'the Pulverizer' not long before Timothy's first mutation.

"' _The Pulverizer' is telling us where the Foot are gonna strike next."_

" _What do you know? He's actually useful."_

" _Yeah, but he can't stay in the Foot. They'll toast him."_

" _Inside information, Donnie. It's worth the risk."_

" _But we're not the ones taking the risk. 'The Pulverizer' is."_

" _I know. It's the perfect plan."_

Much to Leo's remorse, he was just as guilty as Raph for what had become of Timothy. Instead of listening to Donnie like he should have, Leo, too, had put his own agenda first.

" _All right. We'll follow up on his lead, and then, bust the poor guy out of the Foot."_

And when Donatello had once again tried to talk 'the Pulverizer' into getting out of the Foot clan while he still could, Leo had once again been more concerned with getting inside information from the enemy than he had been about Timothy's welfare.

" _Pulverizer, you're in over your head. Go home."_

" _Wait! Not until he finds out more about Shredder's mutation plan."_

Still, Donnie was the only one who seemed to care about Timothy's safety. Donnie had tried to get all of them to see that they were putting Timothy in danger, but Raph had just shot him down again.

" _Guys . . . M – maybe it's not such a great idea sending 'the Pulverizer' into harm's way . . ."_

" _You worry too much, Donnie."_

From there, everything went downhill . . . fast.

" _Shredder's gonna mutate just one Foot soldier first as a test. And guess what? I volunteered!"_

" _What?"_

" _I know! Isn't that cool?"_

" _No! Why would you think that's cool?"_

" _This is my chance to be like you guys. Throw some mutagen on me and boom! I'm a superhero. I'm taking Shredder down!"_

" _The mutagen is dangerous! You have no idea what that stuff could do to you!"_

By the time Leo realized that Donnie had been right all along, it was too late.

" _I knew we should have gotten that guy out when we had the chance!"_ Donnie had said.

It was then that Leo had finally decided it was time to act. How many times had Donnie pleaded with them and warned them? And still, Leo had waited until the human boy was in dire straits to rescue him.

" _Well, we're gonna get him out now. Let's go!"_

Now, more than ever, Leonardo regretted everything about that fateful day. Not just because of what had ultimately happened to Timothy, but because Leo's selfishness and flawed judgment had caused Donnie undue pain. Even after all that Donnie had done to get everyone to listen to him and how hard Donnie had tried to protect Timothy from the inevitable, Donnie still took full responsibility for everything that had happened.

" _Splinter once told me 'the Pulverizer' is my responsibility. I gotta stop him."_

But Donnie couldn't stop Timothy. That was unquestionably not for lack of trying. Donnie had valiantly risked his life to save Timothy, even taking on Dogpound, Fishface, and about a half dozen Foot soldiers all by himself . . . without his weapon no less. But sometimes, you just can't save someone who doesn't want to be saved.

In the end, Timothy had also chosen to ignore all of Donnie's repeated pleas and warnings. The foolish boy had made a conscious decision to self-douse himself in mutagen, and then, after his mutation, he had gone all crazy and attacked them. Yet, Donnie still tried to protect him. If not for Donnie, Timothy would have been blown to smithereens when the warehouse they had been in exploded. Donnie had saved Timothy, but Donnie hadn't seen it that way.

His brothers had all seen that Donnie had done everything he possibly could have to save the hapless boy, but in Donnie's eyes, it still had not been good enough. _He_ still had not been good enough. He had assumed all blame for what had happened and he could not forgive himself.

Now, as Leo stared down at his second youngest brother's bloodshot, dark eyes, he couldn't help but be reminded of the pain he had seen radiating in Donnie's big, brown orbs after Timothy's transformation.

" _I promise, Timothy. One day, I'll turn you back,"_ Donnie had vowed to the former human once they had placed the storage unit that contained Timothy's mutated form in Donnie's lab until Donnie could generate an antidote.

That same pain was still emanating in Donnie's eyes, even after months had passed. Even after his three brothers had tried to convince him that he was not the one responsible for what had come to pass. Still, Donnie continued to blame himself for Timothy's mutation, and now, to make matters worse, Donnie blamed himself for Timothy mutating a second time and going after April. And, as if that hadn't been hard enough on the genius turtle, Donnie then had been forced to take his friend out of commission, possibly forever.

" _Donnie . . . Something's wrong!"_

" _I'm sorry, Timothy."_

" _Wow! Awesome move, Donnie. Real scientific."_

" _Yeah . . . Real scientific . . . Don't worry, my friend. One day, I'll find a cure."_

" _It's okay, Donnie. You did what you had to do. Let's just go home."_

But it wasn't okay. It was anything but okay, because Donnie wasn't okay. He was far from it. Leo knew that now. Perhaps he had known it all along, but he had negligently closed his eyes to the problem, once again leaving Donnie to fix things on his own. Leo would have been a liar if he said he hadn't noticed Donnie missing at mealtimes or that the lights had been left on in the lab in the middle of the night, but had he done something about it? _No_. He had just ignored the signs that something was wrong. They were all guilty of doing the same thing. Leo, Raph, Mikey, and even April all went to Donnie with their problems, calling upon his technical, mechanical, and intellectual skills as well as taking advantage of Donnie's excellent listening abilities and his gift for providing sound, unbiased advice, but when Donnie had a problem of his own, they, more often than not, left him to his own devices. Since Donnie rarely asked for help and spent a majority of his free time in the lab, it was all too easy to overlook him and simply assume that he would take care of things himself. It was no wonder Donnie never talked to any of them about his troubles. None of them ever took the time to listen to him. They only went to him when they needed something . . .

 _Oh, Donnie. Why do you have to do this to yourself?_ Leo thought, suddenly consumed by shame.

"The Timothy thing is all on me, Donnie. How many times do I have to tell you that you have nothing to feel guilty for? You did everything in your power to protect Timothy and get him away from the Foot. If it weren't for me, Timothy wouldn't have still been in the Foot and he never would have gotten mutated. You did all that you could to save him, Donnie. You have to stop blaming yourself for all of this. Can't you see what you're doing, Donnie? You're making yourself sick," Leo said, not even realizing he was gradually inching closer and closer to Donnie and making the already uncomfortable turtle below him even more uncomfortable. Leo could see unshed tears glistening in Donnie's eyes, but his little brother was too stubborn to let them fall. Typical Donnie, fighting with all of his might to hide his feelings, even when his anguish was in plain sight.

"But Timothy went after April because of me," Donnie interjected with a fractured voice that was nothing shy of torture for Leo to hear. Donnie sounded as if there was not a speck of hope left in him. "Even when she's not around us, I still put her in danger. All I ever do is hurt everyone that I care about. Timothy . . . April . . . you guys . . . Maybe things would be better if I – "

Leo could not bear to hear to how Donnie had planned on finishing out that last morbid sentence.

Leo could not bear to hear his little brother's suffering any longer.

"Stop, Donnie! Please, just stop!" Leo implored and his own eyes started to glisten like dewy sapphire pools. With his hands still cupped around Donnie's face, Leo was able to feel that Donnie was now shivering uncontrollably and Leo had a sneaking suspicion that it wasn't from being cold or under the weather. Most likely, it was from Donnie fighting like mad to hold back his emotions.

"I – I can't stop. You don't understand. I promised them I would find a cure, Leo. It's the only way to bring them back . . . and the only way to make things right again. I have to fix all of this, Leo, even if it kills me. I don't care about what happens to me. I promised them I would fix this and that's why I can't stop. Not until I keep my word," Donnie said barely above a whisper, much to Donnie's own mortification. He had tried so hard to make his voice come out stronger, but his efforts came up short and meek.

"I do understand, Donnie. I know you want to keep your promise, but you can't keep doing this to yourself. You may not care what happens to you, but I do, Donatello. I can't watch you do this to yourself. I know you just want to make everything better, but at what cost? Your body can't take the abuse you're putting it through. You've already pushed yourself past the point of exhaustion. If you push yourself any further, you're only going to get worse and you won't be able to help Timothy, Mr. O'Neil, or April if you're down for the count. Making yourself sick isn't going to do them any good and it certainly isn't going to bring them back. I know that you're upset because you think we've lost Timothy and April. I am, too, but I can't lose you over this, Donnie. I don't know what I'd ever do if I lost one of my little brothers," Leo said, starting to pet Donnie's face affectionately.

"Leo . . ." Donnie gasped in despair, peering up at Leo with wide, childlike eyes, silently begging for his brother to help him.

That's when Leo's heart plummeted into the depths of his stomach and he could feel his grasp on his normally steadfast self-control stealing away from him. And just when Leo thought that his heart couldn't possibly sink any lower, Donnie went and proved him wrong.

"I . . . I don't want to . . . I don't want to let them down. I don't . . . I don't want to . . . keep letting . . . everyone down. I'm so . . . tired . . . I don't know . . . what to do anymore . . . It hurts. It . . . it hurts so much," Donnie managed to sputter out, badly. What he had said was almost incoherent due to the internal battle he was engaging in to keep his composure from unraveling.

With that said, Leo's consummate poise all but failed. As his blue mask did an admirable job of absorbing the handful of rogue tears that seeped down from his eyes, Leo bent down so that he could scoop his little brother up into his arms and press him tightly against his plastron.

At first, Donnie stiffened at the unexpected embrace from his somewhat undemonstrative big brother, but when Leo pulled him closer, any form of resistance from Donnie withered away and he willingly melted into his brother's hold, nuzzling his head against the crook of Leo's neck.

"Then let me help you with this burden, Donnie. Please, let me carry some of the weight for you," Leo beseeched his younger brother in earnest as he reached one of his hands up to stroke the back of Donnie's bald head lovingly. Leo's other hand was still clinging to Donnie's shell, helping to hold his brother upright.

"It's not your burden to bear," Donnie mumbled softly into Leo's neck, desperately trying to hold back a sob that kept wanting to slip out.

"It's hurting you, Donnie. That makes it my burden to bear. And not because I'm your leader, but because I'm your big brother. Big brothers are supposed to take care of their little brothers, right?" Leo asked, purposely letting his voice soften uncharacteristically.

Donnie nodded into Leo's neck and Leo rested his cheek on top of Donnie's head. At that moment, Leo could have sworn that he felt Donnie's protective walls come tumbling down.

"You know, there was one more thing on that list of yours that I didn't correct you on, and that was you crashing the Shellraiser through a wall. Do you know why I saved that one for last?" Leo asked and the warm ambiance of Leo's voice was almost like a soothing cradlesong to Donatello's ear slits.

Donnie feebly shook his head against Leo's skin in response to his question and the sleepy turtle began to lean more and more of his weight into his older brother's body, finally accepting Leo's support. Finally allowing himself to relax for the first time in days.

"It's because that one should have never _ever_ made your list. What you did that night was one of the bravest, craziest, single-most selfless acts I've ever seen. I know you worked your shell off to build the Shellraiser and I know how proud you were of it, but I bet you didn't even give a second thought to smashing it straight through that brick wall in order to save Raph's life, did you? You weren't even buckled in and you could have been seriously injured in the crash, but all you cared about was getting the antidote you had made to Raph."

"Any of you would have done the same for me," Donnie muttered and Leo noticed he was nearly holding up all of his brother's weight now, but he didn't mind. In fact, he was thrilled that Donnie was letting him assist him for once.

"True, but the key difference is that none of us would have been able to concoct that antidote for Fishface's venom the way that you had. You were the only one capable of saving Raph's life. The point is, Donnie, you are irreplaceable. You bring something to the team that no one else possibly can and that's what makes you so special and that's what makes you so very important. You have saved our shells so many times with your inventions and your smarts, I've lost count. That's just one of the many, many reasons we need you, Donnie. That's why we need you to take better care of yourself. Because we can't do what we do without you. You are a vital part of this family. Without you, we would fall apart," Leo said, planting a kiss on the top of Donnie's smooth scalp.

"But what about all the mistakes I've made?" Donnie sniveled, but only a little. Leo smiled because it was hopelessly cute. Fortunately, Donnie couldn't see him or he may have gotten embarrassed.

"Donnie, we've all made plenty of mistakes and we will continue to make them, because, last I checked, none of us are perfect. The main thing is that we learn from our mistakes and use them as an opportunity to grow. Mistakes are a part of life that we must come to accept. You cannot blame yourself for every little thing that goes wrong or you'll make drive yourself insane. Believe me, I know," Leo groaned, knowing from personal experience just how hard it was not to assume full blame when things didn't go so well. As leader, Leo had done more than his fair share of shouldering the blame for every mission that wasn't as successful as it could have been or didn't go quite as he had envisioned in his head. Leo had a long track record of mentally beating himself up over what he should have done better or what he could have done differently, constantly overanalyzing and strategizing so that he might improve upon his future performance. He incessantly strove to become that ideal leader that he always dreamed he could be.

Up until now, Leo had thought he was the only brother who had pushed himself to such extremes in order to achieve perfection. He had honestly believed that because he was leader, he was the brother who placed the most blame on himself and the one who felt the most responsible for his brothers' safety, but Leo clearly had been erroneous in his assumption. Donnie obviously felt the same types of obligations weighing down on him. Donnie was just as dedicated to his brothers' safety – as well as his friends' – and he was just as guilty of overthinking things and blaming himself when things didn't go according to plan. Leo was starting to realize that Donnie was growing up to be more like him than he would have ever imagined possible and that filled him with pride.

Donnie then spoke as though he had tapped into Leo's thoughts. "You're just as guilty of blaming yourself when things fail. So how do you deal with it? The guilt, I mean . . . " Donnie asked softly, curling up closer to his brother, dimly aware of the fact that he was cuddling against Leo. It was something that Donnie had not done since he was a turtle tot, back in the days that he would crawl into his big brother's bed after a terrifying nightmare and nestle into the plastron of his much stronger brother.

Feeling a similar sense of nostalgia, Leo snuggled in closer to his little brother before answering his question. "I know it's hard, but you have to learn to let things pass. 'Like a river over stone' as Sensei always says. There are some relaxation techniques that help me to find inner peace and see things in a clearer perspective. Sometimes, I meditate. Sometimes, I practice my katas. Sometimes, I sit down and read a good book. When those things don't work and I still feel troubled about something, I will go and talk to Sensei about how I am feeling. That or I will talk to you about it," Leo said.

Donnie lifted his head and backed away from Leo a slight bit, looking up at his older brother quizzically.

"Me?" Donnie squeaked and he nibbled on his bottom lip timidly.

Leo gave Donnie a great big, toothy smile and soothingly swept away any moisture that may have been adhering to his younger brother's pasty cheeks, knowing that Donnie would be ashamed if his other brothers saw any evidence that he had been crying. Leo then took a moment to quickly wipe his own face off. As the supposedly 'fearless' leader of the brothers, Leo had a reputation to uphold. Leo grimaced at the thought of how his two other brothers would react if they would have seen him crying. In his head, Leo could hear Raph taunting him and calling him 'Weep-O-nardo' or 'Tearful leader.'

Shaking his other brothers out of his thoughts, Leo veered his attention back on Donnie, who was still waiting for a response.

"Yes, you, Donnie. You're the one brother that I can talk to about anything and not have to worry about you making fun of me or blabbing things to everyone else in the Lair. Like I said before, I trust you with my life, Donnie, which means I trust you with all of my secrets as well," Leo said so sincerely, Donnie might have taken him at his word if not for one little detail . . .

"Yeah, like you trusted me with the whole feelings for Karai thing?" Donnie noted with a devious sneer, finally letting his sarcasm manifest itself again.

"That . . . that was different. I didn't tell you about Karai because I was . . . Well, I thought that . . . you and Mikey wouldn't . . . Ah, nevermind . . . " Leo stumbled over his words and his cheeks blushed with humiliation.

Donnie couldn't help but to snicker at his oldest brother's rather tongue-tied reaction.

Although Donnie was laughing at Leo's expense, having successfully made his big brother make a fool of himself, Leo was still elated to hear the sound of Donnie's giggling. It was a welcome reprieve from the funk that Donnie had been in.

"The point I am _trying_ to make here is that you have always been here for me whenever I need someone to talk to, and just as you are here for me, I am always here for you, Donnie. And I mean _always_. If you ever need to get something off of your chest or maybe a shoulder to lean on or a pair of helping hands . . . or just someone to listen to you vent, I want you to know that you can always come to me for anything . . . anytime. You can come to any of us whenever you're feeling down or hurt . . . or alone." Leo paused for breath before continuing. The subject matter was making it hard for him to control the consistency in his voice. "You don't ever have to feel like you're alone, Donnie, because you never are. We will always have your back . . . or your shell, little brother. Because we're your family and we love you very, very much," Leo declared, placing his hands on Donatello's shoulders and giving them a good squeeze.

Donnie eyes started to dampen again, but he didn't notice. He just looked up at Leo with a tentative expression.

"We're going to get through this, Donnie. Even if April never comes back, me and Raph and Mikey . . . we're going to help you through it, but that doesn't mean you should lose hope or give up. I know if anyone can find a cure for Mr. O'Neil and Timothy, it's you, Donnie. But you're going to have to find a cure without putting yourself at risk anymore, understood? From now on, you have to let us help you and you have to take better care of yourself. That means no more skipping meals, no more all-nighters in the lab, no more blaming yourself for everything, and no more shutting us out. Your safety comes first, Donatello. You will not compromise your health again in order to come up with a cure. Is that clear?" Leo asked in that trademark stern tone of his that Donnie knew better than to contend with.

Donnie nodded and lunged forward to wrap his arms around his big brother's shell, pushing his face against Leo's plastron and letting out a small contented sigh. Leo was somewhat taken aback by the force behind the hug, but he gladly returned the display of affection and pulled his little brother as close to him as he could, sheltering Donnie's thin form in the sinewy protection of his arms.

For several minutes, the two of them sat there in silence until Leo began to feel Donnie's body starting to go limp, as if he couldn't hold himself up a second longer.

"You need to get some rest now, Donnie," Leo said, carefully lowering Donnie back down to the mattress.

Sinking into his pillow, Donnie didn't protest, but his stomach did, growling loudly over its lack of nourishment.

"But first, maybe we should get you a little something to eat before you pass out again," Leo said, patting Donnie on the arm as his stomach let out another gurgling sound that made Donnie recoil bashfully.

"Ah, yeah! That's what I'm talkin' 'bout, son! Breakfast in bed, coming right up, D! It'll be totally 'eggscellent!'" Came an exuberant voice from outside of Donnie's room, and then, there was the sound of footsteps leading away from the door.

"What the shell is wrong with you, you moron?" Came a gruff voice that faded down the hall along with the footsteps.

Leo groaned and shook his head from side to side in disgust. Perhaps he had punished the wrong turtle.

"Well, I guess you weren't kidding when you said that you guys would always be here for me. Raph and Mikey can't seem to tear themselves away, even when you ordered them to," Donnie remarked, cynically. "So . . . uh, Leo . . . does this mean that I'm not grounded anymore?" Donnie asked, hopeful of getting his sentence reduced or thrown out.

"I don't know, Donnie. Why don't you let me sleep on it . . . for about five or six days . . ." Leo said with a fiendish grin.

* * *

 _ **To be continued . . .**_


	3. Epilogue - Father Knows Best

_***Disclaimer: I do not own the rights to the Teenage Mutant Ninja Turtles franchise.**_

 _ ***Author's Note: I have had several requests to add to this story, so I decided to put a little TMNT 2012-style ending on it. I really hope you like it. A big thanks to all of you who have favorited/followed me and provided me with such kind feedback for both this story and for 'You're Needed Here Now, Donnie' (aka 'YNHND' per my good friend RascalKat). I really appreciate all of your support!**_

* * *

 **Epilogue – Father Knows Best**

It had been three days since Donnie's collapse in the lab and the genius turtle had finally coerced Leonardo into allowing him to leave the confines of his bedroom on account of good behavior, which hadn't come a moment too soon. Being restricted to his room for three excruciatingly long days had left Donatello feeling strangely claustrophobic and he had grown quite convinced that had he been forced to actually serve out his full prison term, he would not have survived the ordeal. Yes, he was well aware that that had been a slight exaggeration on his part, but being cooped up in a small room for over seventy-two hours straight with your family members taking turns babysitting you gave a turtle a lot more time to overthink and overdramatize things.

The point was, Donnie was thankful for his early discharge.

However, his freedom had come with several strict stipulations that he had not been able to weasel his way out of. The worst of the stipulations had been that he was not allowed to step foot in his lab for the entire duration of his original punishment (five days), nor was he allowed to leave the lair under any circumstances. Not even if there were to be a horrific fire, an unforeseen natural disaster, or a global extinction level event. He had made the mistake of asking about such scenarios and his untimely use of sarcasm had nearly gotten his plea bargain thrown out. Luckily, Leo had been in a stunningly forgiving mood during the negotiation process.

Another condition Donnie had had to agree upon before being permitted to leave his room was an alteration to his routine dietary plan. An intake of at least three meals a day had been mandated, with portion sizes to be determined by Master Splinter and Leonardo until further notice. This directive hadn't seemed so bad at first, until Donnie realized that it meant that he had to eat in front of an audience at all times _and_ he was not allowed to be excused from his meal until literally every last speck on his plate had been consumed. Mikey had even gone so far as to try to make him lick his plate clean a couple of times, but Donnie had flat-out refused, determined to keep some of his dignity intact. No further punishment that they could have dished out could have possibly been worse than that kind of humiliation.

In addition to regulating his eating habits, his family had also put inflexible policies in place regarding his sleeping schedule. All electronic devices, miscellaneous gadgets, and written material had been removed from his room in order for him to focus on getting his required full eight hours of sleep in each night. If he did not willingly comply, Raphael had been given full permission to enforce these new policies however he saw fit, and, however Raph saw fit could be most unpleasant . . .

It went without saying that Donnie wasn't all that enthusiastic about these newly implemented rules and regulations. He had already been inquiring about how long they would remain in effect, but no one would give him a definitive answer. His best guess was a week or two . . . possibly longer, depending on how much time it took for him to earn his family's trust back.

But despite his impatience with all of the recent 'Donnie' guidelines that had been put in place without his say-so, he was feeling much better. Not perfect, but better than he had felt in a long time. Yes, it still pained him that April was out of their lives, and, yes, he still felt guilty for what had happened to Timothy. Those wounds cut deep and still very much afflicted him inside, but, for the first time in months, he did not feel as though he was alone with his torment. For the first time in months, he felt as though he finally had someone he could turn to. Someone who understood his pain . . . Someone who could help him through . . .

And _that_ felt good.

From where he was currently standing, Donnie glanced over his shoulder and flashed a warm smile at his oldest brother. The brainy turtle then turned his attention back to his other two brothers with whom he was playing Atomic Robo-X with. Something he had not done for a long, long time. _Too long . . ._

From across the room, Leo had returned his second youngest brother's smile, keeping the cordial expression in place until Donnie's back was turned to him once again. The eldest turtle's face then fell into a somewhat gloomy frown as he watched his younger brothers from the bench seat that surrounded the sunken area in the main living space of the Lair.

Leonardo couldn't help but to narrow his eyes on his genius brother and the guilt began to eat away at him once more. Even though Donatello had probably gotten more rest and nourishment in the past three days than he had gotten in the last month, he still looked disturbingly frail and skinny. Leo was still worried sick about him.

"What troubles you, my son?" Came the sound of his father's voice, pulling Leonardo out of his dark thoughts and just about giving him a cardiac episode. Once again, Master Splinter had managed to enter the room and walk up right beside him without making a single sound. The old rat's ability to remain virtually undetected was impressive and creepy at the same time.

"I'm not even sure how to begin to answer that question, Sensei," Leonardo said in a voice full of defeat.

Looking down at his eldest son, Master Splinter rested one hand atop his walking staff and held his other hand behind his back. It was a sure sign that Leonardo was about to have some of his father's seemingly infinite wisdom imparted upon him, whether he wanted it or not . . .

"You are still concerned about Donatello," Master Splinter easily surmised as he momentarily shifted his gaze upon his second youngest son, and then, returned his reddish-brown eyes onto his oldest son.

"How could I not have seen what he was doing to himself? How could I have been so blind, Sensei?" Leonardo asked and his shoulders dropped down to better demonstrate his misery.

"Leonardo, you are not responsible for what happened to your brother. That responsibility lies solely with Donatello. Your brother placed far too much burden on himself and chose to neglect his own basics needs. That was of his own doing. You did not force him to make such choices," Master Splinter said flatly.

"But I should have noticed, Sensei. As his leader, I should have noticed that there was something wrong. How could I have missed something so obvious?" Leo asked, raking his hands down his face in frustration.

"Leonardo, being a leader does not mean that you are not allowed to make mistakes. Even the greatest leaders in history have made their fair share of mistakes. What is important is that you learn from those mistakes so that you do not repeat them," Master Splinter said solemnly, but he could still see that his young son was not convinced by his words. His eyes were still full of self-doubt.

"As I said, Leonardo, you are not responsible for your brother's unwise actions. What you _are_ responsible for is helping your brother to get better. Once you realized that Donatello was not taking proper care of himself, you did all that you could to protect your brother from harming himself any further. You acted commendably by ensuring that he was safe and that proper measures were put into place to prevent this from happening again. You learned from your mistake, my child. That is what matters," Master Splinter said, placing a hand on Leonardo's shoulder and squeezing it reassuringly.

Touched by the poignant words of his father, Leonardo peered up at him and his lips curled into a grateful smile.

"I am proud of you, my son," Master Splinter said with a nod of approval.

"Thank you, Sensei," Leonardo said, bowing his head both out of respect and to hide the moisture in his eyes. Feeling a newfound sense of relief, Leo then got up off of the couch and decided to join his brothers around their prized arcade game, claiming dibs on the next turn. He couldn't help but to grin at his three little brothers. He would always be there to help and protect them, just as his father was always there to help and protect him. That's what families were for.

* * *

 _ **The End**_


End file.
